Re: ARCH_FREE_PTE_NR 5350 on x86_64

[Hugh Dickins <hugh@veritas.com>]

On Mon, 15 Oct 2007, Nick Piggin wrote:
> On Monday 15 October 2007 16:54, Alok kataria wrote:
> >
> > Looking at the tlb_flush code path and its co-relation with
> > ARCH_FREE_PTE_NR, on x86-64 architecture. I think we still don't use
> > the ARCH_FREE_PTE_NR of 5350 as the caching value for the mmu_gathers
> > structure, instead fallback to using 506 due to some typo errors in
> > the code.
> >
> > Found this link in the archives.
> >
> > http://www.ussg.iu.edu/hypermail/linux/kernel/0509.1/1821.html
> >
> > I don't think anything has been done on this yet (looked at 2.6.23).
> > Do let me know if its only a typo that needs a fix, or we are still
> > waiting for some other other changes to come into effect.
> 
> ARCH_FREE_PTE_NR should probably just get ripped out completely at
> this point. Something similar (but working) could be added back if
> anybody actually had a workload where it helps to increase the mmu
> batch size.

Agreed.  No hurry, but thanks to Alok for reminding us.
CC'ing Ben since he's the one most active in mmu_gathering these days.
CC'ing Thomas lest he's puzzling over it in the x86 merge.

Hugh